1. Field of the Invention
The present invention relates to wireless communication, and more particularly, to a method of transmitting a data block in a wireless communication system, and a transmitter using the same.
2. Related Art
Recently, various wireless communication technologies have been developed with the development of information communication technology. Among them, a wireless local area network (WLAN) is a technique allowing mobile terminals such as personal digital assistants (PDAs), lap top computers, portable multimedia players (PMPs), and the like, to wirelessly access the Internet at homes, in offices, or in a particular service providing area, based on a radio frequency technology.
As a technology specification that has been relatively recently legislated in order to overcome a limitation in a communication speed that has been pointed out as a weak point in the WLAN, there is the IEEE (Institute of Electrical and Electronics Engineering) 802.11n. An object of the IEEE 802.11n is to increase a speed and reliability of a wireless network and extend an operating distance of the wireless network. More specifically, the IEEE 802.11n is based on multiple inputs and multiple outputs (MIMO) technology in which multiple antennas are used at both of a transmitting end and a receiving end in order to support a high throughput (HT) having a maximum data processing speed of 540 Mbps or more, minimize a transmission error, and optimize a data speed.
A basic access mechanism of the IEEE 802.11 medium access control (MAC) is a carrier sense multiple access with collision avoidance (CSMA/CA) mechanism associated with binary exponential backoff. The CSMA/CA mechanism is referred to as a distributed coordination function (DCF) of the IEEE 802.11 MAC and basically adopts a “listen before talk” access mechanism. In this type of access mechanism, a station (STA) listens to a wireless channel or a medium prior to starting transmission. As a result of listening, if it is sensed that the medium is not used, the listening station starts its own transmission. On the other hand, if it is sensed that the medium is used, the station does not start its own transmission and enters a delayed period determined by the binary exponential backoff algorithm.
Recently, the standardization of IEEE 802.11ac that supports a higher data rate has been progressed. A system supporting the IEEE 802.11ac is referred to as a very high throughput (VHT) system. The VHT system supports dynamic bandwidth allocation, SU/MU-MIMO, and link adaptation.
In order to increase reliability of the data transmission, the WLAN system supports retransmission. If the transmission fails, the data are retransmitted. However, the channel may be good and bad in response to the progress of the retransmission.
There is a need to perform the retransmission while correctly reflecting the channel status.